Asphalt mixtures, generally referred to as ascon, are prepared through the operations in which asphalt, aggregates, mineral fillers, etc. are charged into an asphalt mixing plant and then heated to a high temperature of 160 to 180° C., and the mixtures later undergo cooling down to a room temperature while being applied and compacted on a road. Therefore, there have been problems associated with much energy required for heating to a high temperature and a large amount of harmful gases (e.g. carbon dioxide, sulfur oxides, nitrogen oxides, etc.) emitted during the preparation and application of asphalt mixtures. Also, there are problems in that much time is required for the high-temperature asphalt mixtures to cool down to a room temperature during road paving processes, thereby road openings are delayed and paving crew members are exposed to safety hazards for the duration.
In order to solve such problems, warm-mix asphalt mixtures (WMAs), which can be mixed and compacted at temperatures of 20 to 40° C. lower than those of the conventional hot-mix asphalt mixtures (HMAs), have been active areas of research recently.
For example, Patent Literature 1 discloses a technology related to a warm-mix additive containing a polyethylene wax and reformed fatty acid, and Patent Literature 2 discloses a technology related to a warm-mix additive containing a polyethylene wax and cellulose fibers.
The asphalt mixtures which are prepared from the above technologies using warm-mix additives based on a polyethylene wax have excellent high-temperature properties such as the resistance to plastic deformation; however, there are problems in that they become susceptible to cracking when exposed to an external shock under a low atmospheric temperature as in winter, thereby causing low-temperature cracking.
Therefore, being urgently needed is the development of an asphalt mixture, which is environmentally friendly and economical in such a way that it can be mixed and compacted at temperatures of 20 to 40° C. lower than those of the conventional HMAs, while having an excellent resistance to plastic deformation, thus being highly durable.